Electrode material



of fused baths containing a proportion of an Patented' Dec. 8, 1931 UNITED STATES PATENT OFFICE FRANK H. DRIGGS, OF BLOOMFIELD, NEW JERSEY, ASSIGNOB TO WESTINGHOUSE LAMP COMPANY, A. CORPORATION 01 PENNSYLVANIA ELEGIRODE MATERIAL No Drawing.

This invention relates to the preparation of rare refractory metals and more particularly to the preparation of the rare refractory metals by the electrolytic decompositlon ionized compound of the rare refractory metal.

. One of the objects of the present invention is to provide an electrode material upon which the rare refractory metal may be deposited without accompanying detrimental contamination therewith.

Another ob]ect of this invention is to provide an electrode material which is substantially difiicultly alloyable with the rare refractory metals.

Another'object of this invention is to provide an electrode material which is of relatively low solubility in a fusion mixture comprised substantially of alkaline and alkaline earth metal halides.

Other objects and advantages will become apparent as the invention is more fully disclosed.

In the practice of my invention I employ the electrolytic methods for the reparation of the rare refractory metals rom fused baths, in accordance with the inventions set forth in copending applications Serial Nos. 275,264 filed May 4, 1928; 277,096 filed May 11, 1928; 309,682 filed October 1, 1928; 316,624 filed November 1, 1928; 351,451 filed March 30, 1929 and 441,711 filed April 4, 1930 by Frank H. Driggs and Frank H. Driggs et al., which applications are assigned to the same assignee as the present invention. I have found that such metal powders when deposited upon cathodes of the more common electrode materials, such as carbon, nickel, iron, copper and the like, are seriously contaminated therewith.

With carbon, for example, the contamination appears to be merely the admixing of the carbon particles with the metal powder deposit and in some cases the admixture may be segregated by mechanical means. With nickel, iron andcopper cathodes there ap- .pears to be a definite alloying action, and

the rare refractory metal powders may not 1930. Serial No. 445,228.

be segregated therefrom by either mechanical or chemicabsolution means.

I have found that this alloying action may be entirely eliminated by the use of cathode gnaterial comprised substantially of molybdenum or tungsten. Because of the greater ease of obtaining molybdenum in sheet or strip form, its greater flexibility and comparative cheapness, I prefer to employ this material. Tungsten, however, is equally as useful for the purpose of my invention.

7 In accordance with the practice of the present invention I comprise the cathode of an electrolytic cell, in which the electrolyte comprises a fusion mixture consisting of alkaline and alkaline. earth metal halide compounds containing a proportion of an ionized rare refractory metal compound, such as the double halide compounds, of molybdenum. Preferably the cathode is what is known in the art as a floating type cathode, such as is set forth in application Serial No. 351,451 above identified, and in that case is comprised substantially of sheet molybdenum in strip form. The other electrode is preferably comprised of carbon as this material is not detrimentally attacked by the evolution of gases at the anode.

By the practice of my invention and the use of molybdenum or tungsten cathodes, the rare refractory metals may be deposited thereon without contamination by the cathode material. This is believed to be due to several factors, such as the relative difliculty in effecting the electrolytic deposition of these metals from such fusion mixtures; the relatively great difficulty in forming alloys of molybdenum and tungsten with rare refractory metals; the low rate of diffusion of metals of high atomic volume at temperatures below 1000 C.; and the relatively low solution pressures of the metals in the electrolyte under the highly reducing conditions ordinarily maintained about the cathode in accordance with the practice of the invention set forth in copending application Serial No. 351,451, above identified.

There may be many modifications and adaptations of the present invention but such modifications and adaptations are anticipated as may fall within the scope of the following claim.

What is claimed is:

W The method of preparing-rare refractory metals by the electrolytic deposition thereof from fused baths which includes de ositing said metal onto a, molybdenum catho e.

In testimony whereof, I have hereunto subscribed my name this th day of April,

FRANK H. DRIGGS 

